# Max Planck Institute for Extraterrestrial Physics

The Max Planck Institute for Extraterrestrial Physics is part of the Max Planck Society, located in Garching, near Munich, Germany. In 1991 the Max Planck Institute for Physics and Astrophysics split up into the Max Planck Institute for Extraterrestrial Physics, the Max Planck Institute for Physics and the Max Planck Institute for Astrophysics. The Max Planck Institute for Extraterrestrial Physics was founded as sub-institute in 1963. The scientific activities of the institute are mostly devoted to astrophysics with telescopes orbiting in space. A large amount of the resources are spent for studying black holes in the Milky Way Galaxy and in the remote universe.

## History

The Max-Planck-Institute for extraterrestrial physics (MPE) was preceded by the department for extraterrestrial physics in the Max-Planck-Institute for physics and astrophysics. This department was established by Professor Reimar Lüst on October 23, 1961. A Max-Planck Senate resolution transformed this department into a sub-institute of the Max-Planck-Institute for Physics and Astrophysics on May 15, 1963. Professor Lüst was appointed director of the institute. Another Senate resolution on March 8, 1991, finally established MPE as an autonomous institute within the Max-Planck-Gesellschaft. It is dedicated to the experimental and theoretical exploration of the space outside of Earth as well as astrophysical phenomena.

### Timeline

Major events in the history of the institute include:
* 1963 Foundation as a sub-institute within the MPI für Physik und Astrophysik; director Reimar Lüst
* 1969 Klaus Pinkau becomes director at the institute (cosmic rays, gamma-astronomy)
* 1972 Gerhard Haerendel becomes director at the institute (plasma physics)
* 1975 Joachim Trümper becomes director and scientific member at the institute (X-ray astronomy)
* 1981 The MPE X-ray test facility "Panter" located in Neuried starts operation
* 1985 Gregor Morfill becomes director and scientific member at the institute (theory)
* 1986 Reinhard Genzel becomes director and scientific member at the institute (infrared astronomy)
* 1990 Joachim Trümper together with the MPI for Physics (MPP) founds the semiconductor laboratory as a joint project between the MPE and the MPP (since 2012 operated by the MPG)
* 2000 R. Genzel together with the University of California Berkeley founds the "UCB-MPG Center for International Exchange in Astrophysics and Space Science"
* 2000 G. Morfill together with the IPP founds the "Center for Interdisciplinary Plasma Science" (CIPS) (until 2004)
* 2001 The "International Max-Planck- Research School on Astrophysics" (IMPRS) is opened by MPE, MPA, ESO, MPP and the universities of Munich
* 2001 Günther Hasinger becomes scientific member and director at the institute (X-ray astronomy)
* 2002 Ralf Bender becomes scientific member and director at the institute (optical and interpretative astronomy)
* 2010 Kirpal Nandra becomes scientific member and director at the institute (high-energy astrophysics)
* 2014 Paola Caselli becomes scientific member and director at the institute (Center for Astrochemical Studies)
* 2020 Nobel Prize in Physics for Reinhard Genzel for his research on the black hole at the centre of the Milky Way (Sagittarius A*)
* 2023 Frank Eisenhauer becomes scientific member and director at the institute (infrared-/submillimeter astronomy)

### Detailed history

The Max Planck Institute for Extraterrestrial Physics (MPE) was preceded by the department for extraterrestrial Physics in the Max Planck Institute for Physics and Astrophysics. This department was established by Professor Reimar Lüst on October 23, 1961. A Max-Planck Senate resolution transformed this department into a sub-institute of the Max Planck Institute for Physics and Astrophysics on May 15, 1963. Professor Lüst was appointed director of the institute. Another Senate resolution on March 8, 1991, finally established MPE as an autonomous institute within the Max Planck Society. It is dedicated to the experimental and theoretical exploration of the space outside of Earth as well as astrophysical phenomena. A continuous reorientation to new, promising fields of research and the appointment of new members ensures steady advancement.
Among the 29 employees of the Institute when it was founded in 1963 were 9 scientists and 1 Ph.D. student. Twelve years later in 1975 the number of employees had grown to 180 with 55 scientists and 13 Ph.D. students, and today (status 2015) there are some 400 staff (130 scientists and 75 PhD students). It is noteworthy that permanent positions at the institute have not increased since 1973 - despite its celebrated scientific achievements. The increasingly complex tasks and international obligations have been mainly maintained by staff members with positions having limited duration and funded by external organizations.
Because the institute has assumed a leading position in astronomy internationally, it has attracted guest scientists throughout the world. The number of long-term guests increased from 12 in 1974 to a maximum of 72 in 2000. In recent years MPE has hosted an average of about 50 guest scientists each year.
During the early years, the scientific work at the Institute concentrated on the investigation of extraterrestrial plasmas and the magnetosphere of the Earth. This work was performed with measurements of particles and electromagnetic fields as well as a specially developed ion-cloud technique using sounding rockets.
Another field of research also became important: astrophysical observations of electromagnetic radiation which could not be observed from the surface of the Earth because the wavelengths are such that the radiation is absorbed by the Earth's atmosphere. These observations and inferences therefrom are the subject matter of infra-red astronomy as well as X-ray- and gamma-ray-astronomy. In addition to more than 100 rockets, an increasing number of high-altitude balloons (up to now more than 50; e.g. HEXE) have been used to carry experiments to high altitudes.
Since the 1990s, satellites have become the preferred observation platforms because of their favorable observation-time/cost ratio. Nevertheless, high-flying observation airplanes and ground-based telescopes are also used to obtain data, especially for optical and near-infrared observations.
New observation techniques using satellites has necessitated the recording, processing and accessible storage of high data fluxes over long periods of time. This demanding task is performed by a data processing group, which has grown quickly in the last decade. Special data centers were established for the large satellite projects.
Besides the many successes, there have also been disappointments. The malfunctioning of the Ariane carrier rockets on test launches in 1980 and 1996 were particularly bitter setbacks. The satellite "Firewheel", in which many members of the Institute had invested years of work, was lost on May 23, 1980, because of a burning instability in the first stage of the launch rocket. The same fate was to overtake the four satellites of the CLUSTER-Mission on June 4, 1996, when the first Ariane 5 was launched. This time the disaster was attributed to an error in the rocket's software. The most recent loss was "ABRIXAS", an X-ray satellite built by industry under the leadership of MPE. After few hours in orbit, a malfunction of the power system caused the total loss of the satellite.
Over the years, however, the history of MPE is primarily a story of scientific successes.

### Selected achievements

* Exploration of the Ionosphere and Magnetosphere by means of ion clouds (1963–1985)
* The first map of the galactic gamma-ray emission ( > 70 MeV) as measured with the satellite COS-B (1978)
* Measurement of the magnetic field of the neutron star Her-X1 using the cyclotron line emission (balloon experiments 1978)
* Experimental proof of the reconnection process (1979)
* The artificial comet (AMPTE 1984/85)
* Numerical simulation of a collision-free shock wave (1990)
* The first map of the X-ray sky as measured with the imaging X-ray telescope on board the ROSAT satellite (1993)
* First gamma-ray sky map in the energy range 3 to 10 MeV as measured with the imaging Compton telescope COMPTEL on board CGRO (1994)
* The plasma-crystal experiment and its successors on the International Space Station (1996–2013)
* The measurement of the element- and isotope-composition of the solar wind by the CELIAS experiment on board the SOHO satellite (1996)
* The first detection of water-molecule lines in an expanding shell of a star using the Fabry-Perot spectrometer on board the ISO satellite (1996)
* First detection of X-ray emission from comets and planets (1996, 2001)
* Determining the energy source for ultraluminous infrared galaxies with the satellite ISO (1998)
* Detection of gamma-ray line emission ($^{44}$Ti) from supernova remnants (1998)
* Deep observations of the extragalactic X-ray sky with ROSAT, XMM-Newton and Chandra and resolving the background radiation into individual sources (since 1998)
* Confirmation that a supermassive black hole resides at the centre of the Milky Way Galaxy (2002)
* Detection of a binary active galactic nucleus in X-rays (2003)
* Reconstruction of the evolution history of stars in elliptical galaxies (2005)
* Stellar disks rotating around the black hole in the Andromeda galaxy (2005)
* Determining the gas content of normal galaxies in the early universe (since 2010)
* Resolving the cosmic infrared background into individual galaxies with Herschel (2011)

## Scientific work

The institute was founded in 1963 as a sub-institute of the Max-Planck-Institut für Physik und Astrophysik and established as an independent institute in 1991. Its main research topics are astronomical observations in spectral regions which are only accessible from space because of the absorbing effects of the Earth's atmosphere, but also instruments on ground-based observatories are used whenever possible. Scientific work is done in four major research areas that are supervised by one of the directors, respectively: optical and interpretative astronomy (Bender), infrared and sub-millimeter/millimeter astronomy (Genzel), high-energy astrophysics (Nandra), and in the Centre for Astrochemical Studies (Caselli). Within these areas scientists lead individual experiments and research projects organised in about 25 project teams. The research topics pursued at MPE range from the physics of cosmic plasmas and of stars to the physics and chemistry of interstellar matter, from star formation and nucleosynthesis to extragalactic astrophysics and cosmology.
Many experiments of the Max Planck Institute for Extraterrestrial Physics (MPE) have to be carried out above the dense Earth's atmosphere using aircraft, rockets, satellites and space probes. In the early days experiments were also flown on balloons. To run advanced extraterrestrial physics and state-of-the-art experimental astrophysics, the institute continues to develop high-tech instrumentation in-house. This includes detectors, spectrometers, and cameras as well as telescopes and complete payloads (e.g. ROSAT and eROSITA) and even entire satellites (as in case of AMPTE and EQUATOR-S). For this purpose the technical and engineering departments are of particular importance for the institute's research work.
Observers and experimenters perform their research work at the institute in close contact with each other. Their interaction while interpreting observations and propounding new hypotheses underlies the successful progress of the institute's research projects.
At the end of the year 2022 a total of 508 employees were working at the institute, numbering among them about 100 scientists, 60 junior scientists, 10 apprentices and 140 visiting researchers.

## Projects

Scientific projects at the MPE are often the efforts of the different research departments to build, maintain, and use experiments and facilities which are needed by the many different scientific research interest at the institute. Apart from hardware projects, there are also projects that use archival data and are not necessarily connected to a new instrument. A brief overview of the most recent projects.
* For the EUCLID space telescope, which has been launched in July 2023 and from which researchers hope to gain new insights into dark matter and dark energy, the institute contributed the NISP optical system.
* The GRAVITY instrument enables the four 8-metre telescopes at the Very Large Telescope (VLT) in Chile to be interconnected by means of interferometry to form a virtual telescope with a diameter of 130 metres. The follow-up project GRAVITY Plus is currently being developed, which is expected to achieve an even sharper resolution thanks to a new system of adaptive optics, laser guide stars and an extended field of view.
* For the 39-metre European Extremely Large Telescope (E-ELT), which is currently being built in the Chilean Atacama Desert and is planned to be finished by 2027, MPE is developing the first-light instrument MICADO (Multi-AO Imaging Camera for Deep Observations).
* The ERIS (Enhanced Resolution Imager and Spectrograph) infrared camera will replace the NACO and SINFONI instruments at the VLT.
* With eROSITA (extended ROentgen Survey with an Imaging Telescope Array), the main instrument of the Russian X-ray gamma-ray satellite Spektr-RG launched from Baikonur in July 2019, the first complete sky survey in the X-ray range was achieved.